1. Field of the Invention
The present invention generally relates to landscaping and erosion control mulch and, more particularly, to a sprayable mulch composition formed of 100% cotton plant materials, or a mix of cotton byproduct and/or biomass, and a method of manufacture wherein at least one of the components is fiberized (shredded), steamed and dried so that when the components are mixed the shredded fibers entangle about unshreaded components and/or one another to form a 3-dimensional fiber-entangled matrix. In the manufacture of this mulch, a steaming process contributes to make the mulch fibers more hydrophilic, therefore promoting absorbency of water, dye or pigments, and other performance enhancing agents.
2. Description of Prior Art
It has long been a topic of research to find a way to utilizing the 2.5 million plus tons (calculated from data in 1997 Census of Agriculture) of byproducts from cotton ginning. Some of this research has focused on various applications ranging from using cotton gin byproducts (CGB) as fire logs. Karpiscak et al., Densification of cotton gin trash into fireplace fuel (1982); Beck and Clements, Proc. Of the Symposium of Cotton Gin Trash Utilization Alternatives, National Science Foundation, pp. 87-99. (1982); Ethanol production from cotton gin trash, Proc. of the Symposium of Cotton Gin Trash Utilization Alternatives, National Science Foundation et al., pp. 163-181; Lacewell et al., Pelleting cotton gin trash for energy, Proc. of the Symposium of Cotton Gin Trash Utilization Alternatives, National Science Foundation et al., pp. 141-161 (1982); LePori at al., Energy from cotton gin trash, Proc. of the Symposium of Cotton Gin Trash Utilization Alternatives, National Science Foundation et al., pp. 101-117 (1982); Parnell et al., Converting cotton gin trash into usable energy—technical and economical considerations, Proc. Beltwide Cotton Conferences 2:969-972 (1991); White et al., Conversion of cotton plant and cotton gin residues to fuels by the extruder-feeder liquifaction process, Bioresource-Technology 56:1, 117-123 (1996), livestock feed (Holloway et al., 1974, Feeding gin trash to beef cattle, Bulletin Mississippi Ag. Exp. Stn. 818, 9p; Conner and Richardson, 1987, Utilization of cotton plant residues by ruminants, Journal of Animal Science 65(4) 1131-1138; Poore and Rogers, 1995, Feeding whole cottonseed and other cotton by-products to beef cattle, veterinary-Medicine 90:11, 1077-1087), raw materials in asphalt roofing products (Kolarik and Smith, 1978, Economic evaluation of south plains (Texas) ginning waste as a raw material in the production of roofing felt, Report prepared for Cotton Incorporated, Agreement No. 78-383, 72p), and compost (Hills, 1982, Composting gin trash in California, Proc. of the Symposium of Cotton Gin Trash Utilization Alternatives, National Science Foundation et al., pp. 63-86; Shumack et al., 1991, Using gin trash in composted soil ingredients, Proc. Beltwide Cotton Conferences 1: 498-499; Truhett, 1994, Developing markets for composted gin waste, Proc. Beltwide Cotton Conferences 1:609; Ayers, 1997, Farmer composting of cotton gin trash, Proc. Beltwide Cotton Conferences 2: 1615-1616).
The amount of research that has been performed on this subject is more extensive than indicated in the examples above. For a more thorough overview of previous research efforts, refer to Thomasson, A Review Of Cotton Gin Trash Disposal And Utilization, Proc. Beltwide Cotton Conferences, pages (1990).
Canadian Patent Application No. CA 263,672 by Lloyd discloses a process for manufacturing a mulch material by breaking down vegetable fibers by crushing and/or swelling until the cell structure of said vegetable fibers is opened, separating the fibers, and drying the separated fibers. The mulch material may be used in seed slurries sprayed onto growing surfaces. Lloyd also states that the mulch must be dried at a temperature below 40° C. to ensure that the material is not sterilized and the biologically active bacteria and enzymes are maintained.
More recently, Holt et al. (U.S. Pat. No. 6,383,548) developed a process for converting cotton gin trash and other cotton byproducts into value added products. As described therein, the cotton byproducts are treated with a gellable polysaccharide and subsequently or concurrently ground and compacted. The resultant products may be used as livestock feed, fertilizer, fuel, or mulch. For the mulch, subsequent efforts have focused on improving the workability.
For example, application Ser. No. 11/121,238 by Holt et al. filed 3 May 2005 covers a sprayable or matted mulch composition formed of a mix of cotton byproduct and biomass (hay, grass, kenaf, straw, plant residue, sawdust, wood pulp, paper, etc.), wherein at least one of the components is fiberized (shredded) so that when the components are mixed the shredded fibers entangle about the other component to form a 3-dimensional cross-linked matrix. Specifically, the composition must include at least two components: 1) cotton byproduct (any of burs, sticks, leaves, motes, neps, immature seeds, seed hulls, seed coat fragments, cotton gin byproducts, byproducts from textile mills, byproducts from cottonseed oil mills, and mixtures thereof); and 2) cellulosic (plant derived) hay, grass, kenaf, straw, plant residue, sawdust, wood pulp, paper, or mixtures of any of the above. Either one or both components may be fiberized (shredded), and a preferred ratio of 1) to 2) is 1:9 to 6:4, by weight. The first and second components are sufficiently mixed together to intermingle and entangle the fibers of one component about the other component to form a substantially homogeneous mixture in a 3-dimensional cross-linked matrix. This makes the composition more suitable for use as sprayable hydromulches or as preformed, rolled blankets which are laid upon the soil.
In addition to the foregoing advances, it has now been found that the qualities of spray-on mulch can be improved by altering the production process. More specifically, steaming of the natural fibers followed by drying causes them to shrivel, curl, and physically deform, thereby improving the tendency of the shredded fibers to entangle about the other components to form a 3-dimensional fiber entangled matrix. Steaming also enhances performance by causing the fibers to become more hydrophilic.
U.S. Pat. No. 6,360,478 to Spittle issued Mar. 26, 2002 heating and/or steam treating natural fibers or coating and/or impregnating to create a permanently crimped fiber, and suggests that natural fibers must be heated to relatively high temperatures for a time sufficient to partially break down some of the lignocellulosic or proteinaceous components. However, the extent of the process disclosed requires mechanical crimping or fiber deformation imparted by an external mechanical means in which the fibers are placed in a metal tray in an environmentally controlled oven and are periodically sprayed with a mist of water.
The present inventors have found that a sprayable mulch formed of 100% cotton plant materials, or a mix of cotton byproduct and/or biomass, and a particular method of manufacture that additionally includes fiberizing (shredding) one or all components, coupled with particular steaming and drying steps further promotes the ability to form a 3-dimensional fiber entangled matrix. The present inventors' novel combination of steaming and drying promote fiber entanglement while leaving the fibers malleable enough to be displaced or deformed by plants as they emerge through the mulch from the seedbed below.